Locking thread case for sewing machines



July 8, 194% I o, s I 2248,34?

LOCKING THREAD CASE FOR SEWING MACHINES Filed May 20', 1-939 121 entow WW www 8 WitneSs-MJM 4 20 2 Patented July 8, 1941 LOCKING THREAD CASE FORSEWING MACHINES Otto R. Haas, North Beverly, Mass., assignor to UnitedShoe Machinery Corporation, Borough of Flemington, N. J., a corporationof New Jersey Application May 20, 1939, Serial No. 274,674

14 Claims. (Cl. 112-38) The present invention relates to improvements ina locking thread supply case for a wax thread sewing machine, employinga shuttle of the rotary or oscillatory type for passing loops'of needlethread about the thread case, an example of which is disclosed in U. S.Letters Patent to Gouldbourn et al. No. 1,991,456 dated February 19,1935.

The locking thread case in the machine of the patent is removed from theshuttle when renewing the thread supply and is of generally hollowcylindrical shape, the inner end being open and the front outer endclosed. When introducing a fresh thread supply, the end of thread isinserted through small guide eyes, one at-either side of a tensiondevice in the circular side wall of the thread case for directing thethread from within the thread case through the circular side wall to thetension, and from the tension axially of the thread case along thecircular wall-to the outer surface of the front end Wall before reachingthe work, in order to prevent thread leading from the thread case to thework from being caught by the beak of the shuttle which surrounds thecircular wall of the thread case. The thread case in this type ofvmachine ismaintained by heating devices at a wax melting temperaturewhich renders it uncomfortable to handle when removed from the machineso that it is the practice to wrap the thread case in a cloth or wad of,waste while threading. As a result, the guide eyes may be blocked by thecloth surrounding the thread case. In continued. use of the machine theproblem of replenishing the supply of locking thread, therefore, is amatter of irritation and difficulty on the part of the operator.

The objects of the present invention are to simplify and improvetheconstruction of a looking thread supply case for a machine of thetype referred to in order to facilitate the operation of rethreading thethread case when inserting a fresh supply of thread.

With these and other objects in view, the present invention contemplatesthe provision in a cylindrical locking thread case having one end opento receive a supply of locking threadand a yielding thread tension in acircular side wall thereof, of an arrangement including quick threadingguide eyes at opposite sides of the tension device to direct the threadrespectively through the circular wall of the thread case'to the tensionand from the tension towards the.-

work. In the present embodiment ofthisfeature of the invention the quickthreading guide eye "the thread case and the thread guide eye.

for directing the thread through the circular wall of the thread casecomprises a slot entering the open end of the thread case, and the quickthreading eye at the other side of the tension directs the threadthrough a perforated lug extending radially beyond the circular wall atthe closed end of the thread case beyond the path of the loop takerbeak.

The tension of the thread case in the patented machine is effected by awire spring bent to follow the curvature of the circular thread casewall. To enable the spring to act properly in the prior machine, thespring is located on the circular thread case wallbetween the open endof According to a further feature of the present invention, the tensionspring is arranged at a location which will permit access to the threadguide throughthe open end of the thread case without shortening thespring or rendering it less efiective to regulate the tension.

The front closed Wall of the thread case in the machine of the abovementioned patent has formed in it a groove engaged loosely by a threadcase rotation limiting and retaining member, and

the thread case, it passes between the retaining,

member and the'front thread case wall, the retaining member forcing, thethread in the needle loop towards. the bottom of the groove. In the 1construction hereinafter illustrated, the thread entering slot whichpermits. quickthreading of the thread in the lug is formed along thebottom of the groove which receives the retaining member so that thereisno danger from engagement of the needle loop with the threading slot.

These and other objects of the invention including certain details ofconstruction and combinations of parts will be further explained in thefollowing description, taken in connection with the accompanying drawingand pointed out in the appended claims. In the drawing Figure 1 is aview in right hand side elevation of the front portion of a machineembodying the features of the present invention; Figure 2213 aperspective View showing the closed front end wall and a portion of theside wall of the thread case employed in the machine; Figure 3 isa'perspective view of the thread case showing the open inner end;Figures 4 and 5 are views in elevation partly in' section lookingat theclosed end wall of the thread case and indicating successive steps ofthe threading operation; Figure 6 is a sectional detail view, takenalong the line 6-6 of Figure and Figure '7 is a developed view of thecircular side wall of the thread case.

The invention is illustrated as applied to a locking thread supply casesimilar to that disclosed in the patent to Gouldbourn et a1. aboveidentified. That machine is a waxed thread outso-le shoe sewing machine,and is provided with stitch-forming devices including a curved hookneedle Ill, a continuously rotating discoidal shuttle l2, and acylindrical thread case M removably and rotatably supported within theshuttle. Within the thread case i is mounted a supply of locking threadIii in the form of a bobbin or thread cop and from the supply the threadpasses through the circular wall of the thread case past the .tensiondevice and axially of the thread case through a guide eye formed in 2.lug, as indicated at it, extending radially beyond the circular sidewall of the thread case from the closed front end wall.

The tension device of the illustrated machine comprises a block shapedmember 29 slidable axially of the thread case in a suitably formedguideway on the circular side wall, and at one side the block is.notched to receive the free end of a circumferential bar spring 22surrounding more than 180 degrees of the outer surface along thecircular thread case wall. To prevent escape of the spring 22 axially,the circular wall of the thread lease is grooved so that the wallthickness is reduced about its central portion to provide shoulders 24and 26. The shoulder 24. supports the spring 22 and is formed with arecess 28 to receive a fulcrum lug 38 extending from the spring 22between its ends. At one end of the spring 22 there is a second fulcrumlug 32 engaging the shoulder 24. To maintain the fulcrum lugs of thetension spring in contact with the shoulder 24, a circumferentialadjusting wedge 34 is provided having an inclined toothed portioncooperating with an abutment lug 36 on the tension spring 22 formedbetween the fulcrum lugs 38, 32. The adjusting wedge is retained withinthe groove in the side circular wall of the thread case by reason of itsengagement with more than 180 degrees of arc along the circular sidewall surface, and to maintain the Wedge member accurately in place, itis grooved along its inner surface to fit a rib- 38 along the circularthread case wall. When the lug 36 is separated from the wedge 34 bytemporarily bending the tension spring, the wedge may be movedcircumferentially along the.

thread case wall. As the adjusting wedge 3a is moved circumferentiallyalong the thread case wall, greater or less pressure is exerted by thetension spring 22 to force the block 29 towards the shoulder 26 alongwhich the thread passes.

According to a feature of the present invention there are provided quickthreading guideeyes arranged at opposite sides of the tension block 28to receive the thread by lateral movement thereof rather than byinserting the end of the thread through the eyes, one guide eye beinglocated in the circular thread case wall and one in thelug I8 whichdirects the thread beyond the path of the shuttle beak. In the threadcase of the Gouldbourn et al. patent, the tension spring is so arrangedthat it passes between the guide eye in the circular thread case walland the open end of the thread case. To permit the use of a quickthreading slot entering the open end of the present :thread case, thetension spring 22, as illustrated in Fig. '7, is arranged with respectto the block 26 at a location where it will not bar access to the guideeye and an angular threading slot 48 is formed between the ends of thespring 22, terminating with the thread guide eye as at 42. To strengthenthe thread case around the slot All the circular wall is thickenedsubstantially. The slot 60 is cut into the thickened portion of thethread case wall with its apex pointed away from the thread tensionblock 23 and with that portion of the slot which enters the open end ofthe thread case forming an acute angle with the thread case end wall andalso inclined from the inside of the thread case outwardly in adirection extending away from the thread tension so as to bar passage ofthe thread except when the thread is inclined at a corresponding angle.By so arranging the threading slot 4'3, rotation of the thread supplybobbin or cop within the thread case to such an extent as to provideslack thread will not cause the thread to become displaced from theguide eye.

To secure the thread case in place within the shuttle 12 of the presentmachine as well as in the machine of the patent, there is provided aswinging retainer arm 44 having a projection 36 at its lower endarranged to engage a groove 53 in the front thread case enclosing wall.The groove 38 extends radially along the front wall of the thread caseand into the lug i8 through which the locking thread is guided. From thetension block 20 the locking thread passes at an angle somewhat axiallyof the thread case towards the front surface of the closed end wall andalong the front surface of the end wall towards the work from the guideeye in the lug I8.

To provide a quick threading slot for the guide eye, indicated in thepresent drawing at 53), the lug i8 comprises a reversely bent finger 52forming a slot along the bottom of the groove 68, the terminal of thefinger extending in a direction opposite to the direction in which theshuttle rotates. At the end of the finger 52 there is an outwardlyinclined surface 54 arranged to prevent the thread of the needle loop,indicated in Fig. 2 at 56, from becoming caught on the finger as it iscarried about the thread case by the shuttle. The end wall of the threadcase also has a projecting portion 58 extending over the end of thefinger 52 to assist in directing the needle loop away from the end ofthe reversed finger. As afurther means for preventing the needlethread'from becoming caught on the finger 52, a cam surface Gil isformed along one edge of the thread case for lifting each needle loopclear of the reversed end of the finger 52.

In threading the illustrated thread case, the supply reel or pop i6 isfirst inserted in the usual way with a short length unwound at the end.The portion of the thread close to the unwound end is then carriedlaterally through the threading lot 49, along the circular wall of thethread case beneath the tension block 29 and under the finger 52 into anenlarged sight opening 62 formed near the end of the reversed finger 52,as illustrated in Fig. 4. 'The. sight opening 62 is conveniently locatedfor inspecting the amount of' lockingithread remainingin the supplyduring operation of the machine, thus rendering the thread supplyvisible at .all times. After enterin'g'the opening" 62, the unwound endof thread is moved laterally in a reverse direction until it engages theinclined surface 54 at the end of the finger 52. The inclined surface 54causes the thread to be carried towards the right, as shown in Figure 5,into the slot along the bottom of the groove 48, and thereafter a slighttension on the thread will cause it to assume the proper position in theguide eye 55 Having thus described the invention, what is claimed is:

1. A hollow cylindrical locking thread case for a lock-stitch shoesewing machine comprising a circular side wall and an end wall, theremaining end of the thread case being open to receive a supply ofthread, a yielding thread tension on the circular side wall, and quickthreading guide eyes having open-ended thread entering slots at oppositesides of the tension to direct the thread respectively through thecircular wall of the thread case to the tension and from the tensiontowards the work.

2. A hollow cylindrical locking thread case for a lock-stitch shoesewing machine comprising a circular side wall and an end wall, theremaining end of the thread case being open to receive a supply ofthread, a yielding thread tension on the circular side wall, a quickthreading guide eye in the circular wall of the thread case having aslot entering the open end of the thread case to direct the thread fromWithin the thread case to the tension, and a quick threading guide l eyecomprising a perforated lug extending radially beyond the circular wallat the closed end of the thread case and having a thread entering slotbetween the lug and the circular wall of the thread case to directthread from the tension towards the work.

3. A hollow cylindrical locking thread case for a lock-stitch shoesewing machine comprising a circular side wall and an end wall, theremaining end of the thread case being open to receive a. supply ofthread, a yielding thread tension on the circular side wall, and a quickthreading guide eye having an open-ended threading slot entering theopen end of the thread case to direct the thread through a circular wallof the thread case to the tension.

4. A hollow cylindrical locking thread case for a lock-stitch shoesewing machine comprising a circular side wall and an end wall, theremaining end of the thread case being open to receive a supply ofthread, a tension member on the circular wall of the thread case, aguide eye in the circular wall of the thread case having a quickthreading slot entering the open end of the thread case, and acircumferential spring surrounding more than 180 degrees of the outersurface along the circular wall of the thread case with one end engagingthe tension member and the other end at the opposite side of thethreading slot from the tension member.

5. A hollow cylindrical locking thread case for a lock-stitch shoesewing machine comprising a circular side wall and an end wall, theremaining end of the thread case being open to receive a supply ofthread, a guideway in the circular side wall of the thread case, asliding thread tension member in the guideway, a circumferential barspring surrounding more than 1.30 degrees of the outer surface along thecircular wall of the thread case and having one end engaging the tensionmember, and a thread guide eye in the circular wall of the thread casehaving a quick threading slot entering the open end of the thread caseand passing between the tension member and the other end of the spring.

6. A hollow cylindrical locking threadcase for a lock-stitch shoe sewingmachine comprising a circular side wall and an end wall, the remainingend of the thread case being open to receive a supply of thread, aguideway in the circular side wall of the thread case, a slidingthread'tem sion member in the guideway, a circumferential bar springsurrounding more than 180 degrees of the outer surface along thecircular wall of the thread case, said spring having one end engagingthe tension member and a pair of spaced fulcrum lugs with an abutmentlug therebetween, a circumferentially slidable adjusting membercooperating with the abutment lug to tension the spring, and a threadguide eye in the circular wall of the thread case having a quickthreading slot entering the open end of the thread case and passingbetween the ends of the circumferential spring and adjusting member todirect the thread from the inside of the thread case to the tensionmember.

'7. A hollow cylindrical'locking thread case for a lock-stitch shoesewing machine comprising a circular side wall and an end wall, theremaining end of the thread case being open to receive a supply ofthread, a guideway in the circular side wall of the thread case, asliding thread tension member in the guideway, a circumferential barspringsurrounding the outer surface along the circular wall of thethread case and having a fulcrum lug between the ends, another fulcrumlug at one end and an abutment lug between said fulcrum lugs, theopposite end of the spring engaging the tension member to actuate ittowards a surface on the thread ease, a circumferentially slidableadjusting member cooperating with the abutment lug to tension thespring, and a quick threading guide eye in a circular side wall of thethread case having a slot passing between the fulcrum lug at the end ofthe spring and the tension member.

8. A hollow cylindrical locking thread case for a lock-stitch shoesewing machine comprising a circular side wall having a thickenedportion and a front end wall, the remaining end being open to receive asupply of thread, a thread tension on the circular wall of the threadcase, a guide eye in said circular" wall having a quick threading slotof angular shape in the thickened portion of said wall entering the openend of the thread case, the apex of said slot being pointed away fromthe thread tension, and that portion of the slot which enters the openend of thread case being out at an acute angle through the thread casewall from the inside of the thread case away from the thread tension.

9. A lock-stitch shoe sewing machine having, in combination, a hookneedle, a rotary loop taker, a hollow cylindrical thread case rotatablysupported by the loop taker and formed with a circular side wall and afront end Wall, the remaining end of the thread case being open toreceive a supply of thread, a groove on the outer surface of the frontwall, a retaining arm on the machine having a projection engaging thegroove, a quick threading guide eye in the front wall of the thread casehaving a thread entering slot along the groove beneath the projection ofthe retaining arm, and. a cam surface on the front wall of the threadcase for lifting each needle loop carried by the loop taker about thethread case clear of the entrance to said slot.

10. A lock-stitch shoe sewing machine having, in combination, a hookneedle, a rotary loop taker, a hollow cylindrical locking thread caserotatably supported by the loop taker and formed with a circular wall,and a front end wall having a reversed finger extending in a directionopposite to the direction of loop taker rotation to provide a quickthreading guide eye and a cam surface on the end wall of the thread casefor lifting each needle loop carried by the loop taker about the threadcase clear of the reversed end of the finger 11. A lock-stitch shoesewing machine having, in combination, a hook needle, a rotary looptaker, a hollow cylindrical locking thread case rotatably supported bythe loop taker and formed with a circular wall, a front end wall, and areversed finger extending in a direction opposite to the direction ofloop taker rotation to provide a quick threading guide eye and having asurface at its end inclined outwardly in the direction of loop takerrotation from within the thread case to assist in directing each needleloop carried by the loop taker about the thread case away from the guideeye.

12. A lock-stitch shoe sewing machine having, in combination, a hookneedle, a rotary loop taker, a hollow cylindrical locking thread caserotatably supported by the loop taker and formed with a circular wall, afront end wall, a reversed finger extending in a direction opposite tothe direction of loop taker rotation to provide a quick threading guideeye and having a, Surface at its end inclined outwardly in the directionof loop taker rotation from within the thread case to assist indirecting each needle loop carried by the loop taker about the threadcase away from the guide eye, and a projection on the front end walloverlying the end surface of the finger for shielding the end of thefinger from contact with each needle loop carried by the loop takerabout the thread case.

13. A lock-stitch shoe sewing machine having, in combination, a hookneedle, a rotary loop taker, a hollow cylindrical locking thread caserotatably supported by the loop taker and formed with a circular sidewall and a front end wall having a reversed finger extending in adirection opposite to the direction of loop taker rotation to form aquick threading slot between the reversed end of the finger and the edgeof the circular thread case wall, the end of the finger extending intoan opening in the thread case end wall and a cam surface on the end wallof the thread case for lifting each needle loop carried by the looptaker clear of the opening in the front thread case wall.

14. A lock-stitch sewing machine having, in combination, a curved hookneedle, a rotary shuttle, a locking thread case Within the shuttlecomprising a circular side wall and a front end wall having a radialgroove, the other end being open to receive a supply of locking thread,the front end wall having a quick threading guide eye at the bottom ofthe groove and a thread entering slot which passes along the groove, anda rotation limiting retainer cooperating with the groove to hold thethread case from movement with the shuttle.

OTTO R. HAAS.

